evaluation of the effect of nest posture on the sleep-wake state of premature infants

background: premature birth is a major cause of infant mortality in developed countries. newborns confined to neonatal intensive care units (nicus) are in a rapid stage of brain development. as such, sleep plays a pivotal role in the proper brain development of newborns. however, this developmental aspect is often disregarded due to the lack of information. aim: this study aimed to evaluate the effect of nest posture on the sleep-wake state of premature infants. method: this cross-over clinical trial was conducted on 60 premature infants admitted in the nicu of ghaem hospital in mashhad, iran in 2015. infants were divided into two groups of experimental and control. data were collected using the assessment of premature infants' behavior (apib). neonates in the control group were placed in an incubator, and neonates in the experimental group were positioned in a nest. between-group comparison was performed using paired-samples t-test for normal variables and wilcoxon test for non-normal variables. results: in this study, no statistically significant differences were observed between the two groups in terms of the scores of deep sleep state before (p=0.50) and after the intervention (p=0.59). however, during the intervention, mean score of deep sleep was higher in the experimental group (p=0.08). moreover, mean score of slow wake state had no significant difference between the study groups before (p=0.67), after (p=0.86), and during the intervention (p=0.81). implications for practice: according to the results of this study, nest posture increased the deep sleep hours of premature infants as the most imperative state of brain development. therefore, it is recommended that nest posture be used to improve the deep sleep state of premature infants.